Ryan J. Hooper -- DPF, May 24-28, 2002

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Searching For Searching For Large Extra Dimensions at Large Extra Dimensions at

DD

• Extra dimensionsExtra dimensions• Overview of Run 1 resultsOverview of Run 1 results• Run 2 expectationsRun 2 expectations• Current Run 2 dataCurrent Run 2 data

– The diEM channelThe diEM channel– The diThe di channel channel

• SummarySummary

Ryan J. Hooper (University of Notre Dame)Ryan J. Hooper (University of Notre Dame)On behalf of the DOn behalf of the D Collaboration Collaboration

Ryan J. Hooper -- DPF, May 24-28, 2002

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• String Theory yearns for n=6,7 extra dimensionsString Theory yearns for n=6,7 extra dimensions– Compactified with radius R ~ 10Compactified with radius R ~ 10 -32-32mm– Astrophysical and table top experiments: Astrophysical and table top experiments:

– Ruled out n=1 and put significant Ruled out n=1 and put significant constraints on n=2constraints on n=2– Placed limits on R < 0.15mmPlaced limits on R < 0.15mm

• ““Large” Extra Dimensions (LED)Large” Extra Dimensions (LED)– Arkani-Hamed, Dimopoulos, Dvali (ADD) hep-th/9809124Arkani-Hamed, Dimopoulos, Dvali (ADD) hep-th/9809124– Graviton is only particle that propagates in extra dimensionsGraviton is only particle that propagates in extra dimensions– Effective Planck scale (MEffective Planck scale (MSS) down to TeV ranges) down to TeV ranges

– A solution to the hierarchy problemA solution to the hierarchy problem– Kaluza-Klein modes of the graviton (GKaluza-Klein modes of the graviton (GKKKK) can enhance effects at colliders) can enhance effects at colliders

Extra DimensionsExtra Dimensions

nnSPl RMM 22

Ryan J. Hooper -- DPF, May 24-28, 2002

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• At DAt D we look for direct G we look for direct GKKKK production production– Strong n dependenceStrong n dependence

• 1/(MS)n+2

– Gluon or vector boson + EGluon or vector boson + ETT

– EETT from graviton from graviton

escaping detectionescaping detection

• We look at virtual GWe look at virtual GKKKK

exchange as wellexchange as well– Weaker n dependence Weaker n dependence

– F/MF/MSS44

– F = 1 (GRZ)F = 1 (GRZ) = log(M= log(MSS

22/M/M22) for n=2, 2/(n-2) n>2 (HLZ)) for n=2, 2/(n-2) n>2 (HLZ)

= 2= 2//; ; = ±1 (Hewett) = ±1 (Hewett) USED FOR THIS TALK!USED FOR THIS TALK! – Two lepton or two vector boson final statesTwo lepton or two vector boson final states

Extra Dimensions at DExtra Dimensions at D

82

4 SM

GKK

gq

q GKK

gg

g

GKK

GKK

GKKGKK

V

VV V

Ryan J. Hooper -- DPF, May 24-28, 2002

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DD Run 1: Direct G Run 1: Direct GKKKK Search Search• P-pbar P-pbar gluon + G gluon + GKKKK • Final state jet + EFinal state jet + ETT

• Recent monojet resultRecent monojet result– ~79pb~79pb-1-1 of Run 1 data of Run 1 data– EETT > 150 GeV > 150 GeV

– Leading Jet: ELeading Jet: ETT > 150 GeV > 150 GeV– ||– Gives complementary limitGives complementary limit

to LEP results for n > 4to LEP results for n > 4

Ryan J. Hooper -- DPF, May 24-28, 2002

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• Final states are dileptons or diphotonsFinal states are dileptons or diphotons• In Run 1 looked at dielectrons + diphotonsIn Run 1 looked at dielectrons + diphotons

– For better sensitivity For better sensitivity combine e and combine e and to form “diEM” to form “diEM”

• Invariant mass vs. |cos(Invariant mass vs. |cos()|)|• LEDs at high mass LEDs at high mass

and low |cos(and low |cos()|)|

• ResultsResults– 127pb127pb-1-1 of data of data– EETT > 45 GeV > 45 GeV– ||| < 2.5| < 2.5– EETT < 25 GeV < 25 GeV

• LEP: MLEP: MSS > ~ 0.5-1.2 TeV > ~ 0.5-1.2 TeV

DD Run 1: Virtual G Run 1: Virtual GKKKK Search Search

MMSS > 1.1 TeV > 1.1 TeV for for

MMSS > 1.0 TeV > 1.0 TeV for for

q,g q,g

e,

e,

Ryan J. Hooper -- DPF, May 24-28, 2002

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DD Run 2 Expectations Run 2 Expectations• Run 1: 0.13fb-1 • In Run 2

• CM energy 1.96 TeV vs. 1.8 TeV in Run 1• Run 2a: 2fb-1 doubling MS sensitivities over Run 1

• Run 2b: 15fb-1 tripling MS sensitivities over Run 1• Upgraded DD detector

• Our current Run 2 LED analysis follows the Run 1 virtual GKK analysis previously mentioned• Also add the dimuon channel

Ryan J. Hooper -- DPF, May 24-28, 2002

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DD Run 2: DiEM Zs Run 2: DiEM Zs» The Z is a good place to “calibrate” high PT objects» Using ~10pb-1 of data» We see Z to diEM» Cuts:» Standard DStandard D EM ID EM ID» EETT > 20 GeV > 20 GeV» EETT < 30 GeV < 30 GeV» ||| < 1.1 or | < 1.1 or

1.5 < |1.5 < || < 2.5| < 2.5

Central + End Cap

Central + Central

Ryan J. Hooper -- DPF, May 24-28, 2002

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DD Run 2: LEDs DiEM Channel Run 2: LEDs DiEM Channel We see 2 high mass eventsWe see 2 high mass events

Monte Carlo Data

D Run 2 Preliminary

Ryan J. Hooper -- DPF, May 24-28, 2002

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» Highest mass diEM candidate

No extra dimensions yet…but let’s not forget the electron’s heavier No extra dimensions yet…but let’s not forget the electron’s heavier brother!brother!

DD Run 2: DiEM Channel Run 2: DiEM Channel

D Run 2 Preliminary

M(diEM) = 376 GeV; cos* = 0.79; MET = 8.2 GeV;

EM2EM1

ET = 109.7 GeV = -2.10 = 2.19No track match

ET = 115.4 GeV = 0.10 = 5.27No track match

Ryan J. Hooper -- DPF, May 24-28, 2002

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DD Run 2: Di Run 2: Di Resonances Resonances» Once again lets use well known physics to “calibrate”» ~10pb-1 of data» Cuts: » DD Muon ID » Both muons || < 1.6 » Pt tracks > 2.5 GeV

» For Z plot:Track Pt > 15 GeV

D Run 2 Preliminary

Green Histograms = Opposite sign muons

Blue Histograms = Same sign muons

J/

Upsilon

Z

Ryan J. Hooper -- DPF, May 24-28, 2002

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• We see a few high mass eventsDD Run 2: LEDs Di Run 2: LEDs Di Channel Channel

D Run 2 Preliminary

Monte Carlo Data

Ryan J. Hooper -- DPF, May 24-28, 2002

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SummarySummary• Extra dimensions can bring the effective Planck Extra dimensions can bring the effective Planck

scale down to TeV energies scale down to TeV energies • DD in Run 1: in Run 1:

• Direct GDirect GKKKK production results complementary to LEP limits production results complementary to LEP limits for n > 4for n > 4

• Virtual GVirtual GKKKK exchange limits of M exchange limits of MSS > 1.1 TeV for > 1.1 TeV for = +1 = +1 • and Mand MSS > 1.0 TeV for > 1.0 TeV for = -1= -1

• DD in Run 2: in Run 2:• With 2fbWith 2fb-1-1, sensitivity to M, sensitivity to MSS should double vs. Run 1 should double vs. Run 1• Virtual GVirtual GKKKK exchange in diEM and di exchange in diEM and di• We currently have J/We currently have J/, Upsilon and Z resonances, Upsilon and Z resonances• See some higher mass events See some higher mass events

• Should have first physics results by ICHEPShould have first physics results by ICHEP